I've been waiting 31 days for mine and lm not too concerned. In the UK, where I'm from, SN is a reportable substance, which means suspicious purchases need to be reported. But purchasing it is not actually a punishable offence. I dont think its standard practice to seize it at customs, as for all they know you could own a business. I cant speak for every country in the western world, but I think that levels of restriction are pretty much unanimous, in that it isnt illegal in many (if any) countries, due to it's useful purposes in food prep.
There have been many threads asking about seizure of SN at customs, and I've yet to see anyone reply saying theirs was taken. So I think its highly unlikely yours would be.
I'm not concerned about mine, as I know several other people have got theres after waiting longer than me.
I think looking at your post history that you might be Canadian? I know from speaking to other people from Canada on here, that it is quite common for Canadians ordering SN to order from Ukraine, Russia, or somewhere else in that region. Bare in mind if you are doing the same, that this is one of the longest postal routes in the world, and expect for it to potentially take over a month.